The present invention is related to an apparatus for removing residues, in particular plastic residues, from parts of plastics processing machines.
German patent No. DE-PS 37 12 640 discloses an apparatus for removing plastic residues from parts of plastics processing machines which includes a vessel closed in air tight manner by a lid and containing a heat transfer fluid which is heatable to a temperature above the melting point of the plastic material adhering to the parts. Immersing within the heat transfer fluid is a disk operatively connected to a compressed-air vibrator so as to oscillate the heat transfer fluid for supporting the cleaning action. Placed on the lid is a tubular casing box which accommodates the vibrator. A pipe connects the interior of the vessel with the casing box via an activated charcoal filter so that vapor and gases may escape therethrough and are suitably filtered before being released to the atmosphere. The vessel is further connected via an overflow with a collecting receptacle.
Although plastic material adhering to the parts will usually not be decomposed so that the formation of toxic or other obnoxious gases is prevented which otherwise would require a stationary installment of the cleaning apparatus and its equipment with a suitable exhaust system, such a cleaning apparatus has the drawback that the heating and the cooling of the heat transfer fluid especially when vessels of large volume are concerned takes usually a long time. To shorten the heating time by increasing the heating capacity is possible only to a very limited degree because that could easily lead to local overheating and ensuing decomposition of the heat transfer fluid. A further drawback of this known cleaning apparatus resides in the fact that at temperatures of up to 400.degree. C., the air volume prevailing above the liquid level decomposes part of the heat transfer fluid and frequently also the removed plastic material through oxidation. Such decomposition is even more prevalent with increased duration of the heating stage as well as of the actual cleaning stage and of the cooling stage.
The German publication No. DE-GM 78 20 264 describes a container for cleaning metal parts by means of a cleaning liquid. The container accommodates an impeller pump within a tubular pump compartment which is defined by an axis extending parallel to the center axis of the treatment chamber and is connected with the treatment chamber via an upper channel and a lower channel. The impeller pump and additional deflectors cause the cleaning liquid to flow at a very high flow rate of up to 40 m/s in order to improve the cleaning by flowing around the metal parts.